1. Field
The present disclosure relates to the manipulation of virtual three-dimensional (3D) objects, and, in one particular example, to the manipulation of the orientation of virtual 3D objects using a non-hemispherical arcball.
2. Related Art
Developing and animating 3D scenes requires the placement and movement of virtual 3D objects. This typically requires changing the orientation, position, and scale of the objects in a virtual scene or in an object editing environment. The orientation, position, and scale of objects are manipulated through rotation, translation, and scaling techniques.
One way for a user to achieve these manipulations is to directly enter numerical values corresponding to the desired manipulation. For example, a user can change the orientation of an object in 3D space in a computer program by selecting the object and indicating values for three rotation properties, each of which control the rotation about an individual axis X, Y, or Z. While directly entering numerical values for rotation provides a precise method for manipulating the orientation of a 3D object, it presents numerous challenges. For example, the interface is not user-friendly for a user who is not intimately familiar with the rotation settings.
Another way for a user to manipulate a virtual 3D object is to use a pointing device. A change in the location of the pointing device along a detection surface can be used to change the orientation of the object in 3D space. When the user selects two locations on the detection surface using the pointing device, the computer program can rotate the 3D object using the coordinates of the two locations. While using a pointing device for manipulating a 3D object is much more user friendly than directly entering numerical values, it is challenging for users to manipulate the object with a high degree of precision.
Existing systems fail to provide user-friendly manipulation of virtual 3D objects that provide a high degree of precision. Accordingly, a technique for smoothly manipulating 3D objects in 3D space that is user-friendly, intuitive, and precise is highly desirable.